[Qemu-devel] [PATCH 4/5] Make MMIO address page aligned in guest.

[Gleb Natapov <gleb@redhat.com>]

MMIO of some devices are not page aligned, such as some EHCI
controllers and virtual Realtek NIC in guest. Current guest
bios doesn't guarantee the start address of MMIO page aligned.
This may result in failure of device assignment, because KVM
only allow to register page aligned memory slots. For example,
it fails to assign EHCI controller (its MMIO size is 1KB) with
virtual Realtek NIC (its MMIO size is 256Bytes), because MMIO
of virtual Realtek NIC in guest starts from 0xf2001000, MMIO of
the EHCI controller will starts from 0xf2001400.

MMIO addresses in guest are allocated in guest bios. This patch
makes MMIO address page aligned in bios, then fixes the issue.

qemu-kvm commit ccc9b91a1fdfac4161461a519e10a233f5066d2f

Signed-off-by: Gleb Natapov <gleb@redhat.com>
---
 src/pciinit.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/src/pciinit.c b/src/pciinit.c
index 29b3901..53fbfcf 100644
--- a/src/pciinit.c
+++ b/src/pciinit.c
@@ -10,6 +10,7 @@
 #include "biosvar.h" // GET_EBDA
 #include "pci_ids.h" // PCI_VENDOR_ID_INTEL
 #include "pci_regs.h" // PCI_COMMAND
+#include "paravirt.h"
 
 #define PCI_ROM_SLOT 6
 #define PCI_NUM_REGIONS 7
@@ -158,6 +159,12 @@ static void pci_bios_init_device(u16 bdf)
                 *paddr = ALIGN(*paddr, size);
                 pci_set_io_region_addr(bdf, i, *paddr);
                 *paddr += size;
+                if (kvm_para_available()) {
+                    /* make memory address page aligned */
+                    /* needed for device assignment on kvm */
+                    if (!(val & PCI_BASE_ADDRESS_SPACE_IO))
+                        *paddr = (*paddr + 0xfff) & 0xfffff000;
+               }
             }
         }
         break;
-- 
1.6.3.3